1. Technical Field
This disclosure relates generally to a power-supply apparatus which is compact in structure and capable of minimizing adverse effects of electromagnetic noise.
2. Background Art
Hybrid vehicles or electric vehicles usually employ a power-supply apparatus such as a DC-DC converter or a battery charger equipped with a DC-DC converter. Japanese Patent First Publication No. 2000-14149 discloses such a type of power-supply apparatus which is equipped with electronic parts such as semiconductor devices in which switches are fabricated, a choke, and a transformer. The electronic parts are fabricated on a mounting surface of a wiring board disposed on a base plate.
The above power-supply apparatus, however, faces the following drawbacks.
The large number of electronic parts are, as described above, arranged on the wiring board, thus requiring a need for securing an area on the base plate which is large enough to install the electronic parts. This results in an increased overall size of the power-supply apparatus.
The electronic parts are placed on the same level or horizontally, thus needing to secure an interval between adjacent ones of the electronic parts, which leads to an increase in overall length of wire connecting the electronic parts together. Such an increase will result in an increase in electric resistance of the wire, thus causing a loss of electric energy. This lowers the efficiency in operation of the power-supply apparatus. The increase in overall length of the wire will also result in an increase in loop area of the wire, thereby increasing the possibility of electromagnetic noise.
A part of the electromagnetic noise emitted from the wiring board on which the electronic parts are mounted toward the base plate is blocked by the base plate, while the other part of the electromagnetic noise radiating away from the wiring board may affect operations of peripheral devices.